1. Field of the Invention
The invention relates to a control and monitoring system for a power system which controls a monitoring control object by supplying a control instruction from a master unit to a plurality of input/output terminal devices provided for each of a plurality of monitoring control objects in a power system of a substation or the like.
2. Description of the Related Art
A control and monitoring system for a power system of a substation or the like monitors, for example, voltage fluctuation, current changes, power flow changes, and line abnormalities, and according to these states, supplies a control instruction from a master unit to a plurality of input/output terminal devices provided for each of a plurality of monitoring control objects and controls a monitoring control object such as switching control of a transformer tap as a monitoring control object and ON/OFF control of circuit breakers and disconnecting switches as monitoring control objects of the power system in the substation or the like.
When supplying a control instruction from the master unit to the plurality of input/output terminal devices, the master unit grasps information on, for example, a current state (position) of a transformer tap as a monitoring control object and ON/OFF states of circuit breakers and disconnecting switches as monitoring control objects, and according to the information, an input/output terminal device appropriate for controlling is selected and an appropriate control instruction is supplied to the selected input/output terminal device.
Conventionally, as one of the control methods, when starting control, before a control object is selected among the plurality of input/output terminal devices, the master unit collects the information to be used for judging whether control such as interlock check, etc., is possible, and based on the information, selects an input/output terminal device of the control object, and outputs a control instruction (hereinafter, referred to as “conventional method 1”).
In this conventional method 1, in detail, the procedures shown in FIG. 4(a) are followed. Namely, first, the master unit side requests the respective input/output terminal devices BCU1 through BCUn to transmit the information CI to be used for judging controllability (information on the states of the monitoring control object such as a transformer tap state (position) and ON/OFF states of circuit breakers and disconnecting switches) (step A). Next, on the input/output terminal device BCU side, the respective input/output terminal devices BCU1 through BCUn receive the transmission request (of step A) (step B). Then, on the input/output terminal device BCU side, the information CI to be used for judging controllability is transmitted from the input/output terminal device BCU1 through BCUn (step C). Then, the master unit side receives the information CI to be used for judging controllability from the respective input/output terminal devices BCU1 through BCUn (step D). Thereafter, the master unit side makes judgement of controllability based on the received information CI, and when control is possible, the master unit side (1) selects, for example, the input/output terminal device BCU1 as a control object (step E), and (2) notifies the input/output terminal apparatus BCU1 selected as a control object that it was selected as a control object (step F). Then, the input/output terminal device BCU1 selected as a control object receives the control object selection notification (of step F) (step G). After the input/output terminal device BCU1 receives the control object selection notification (of step F) (step G), the master unit side instructs the control object input/output terminal device BCU1 to execute control (step H). Thereafter, the input/output terminal device BCU1 selected as a control object receives the control execution instruction (of step H) (step I), and executes control (step J).
In this conventional method 1, as described above, the information CI (information on the states of monitoring control objects such as the transformer tap state (position) and ON/OFF states of circuit breakers and disconnecting switches as described above) is collected first, so that at the time when the input/output terminal device BCU1 selected as a control object executes control (step J), the information CI may become old (different from the current information), and therefore, proper control may not be performed.
Therefore, in order to improve this, in some methods, the information CI to be used for judging controllability is collected after selection of the input/output terminal device and notification of the selection (hereinafter, referred to as “conventional method 2”).
This conventional method 2 is carried out according to the procedures shown in FIG. 4(b) in detail. Namely, first, the master unit side (1) selects, for example, the input/output terminal device BCU1 as a control object (step E), and (2) notifies the input/output terminal device BCU1 selected as a control object that it was selected as a control object (step F) . Then, the input/output terminal device BCU1 selected as a control object receives the control object selection notification (of step F) (step G). Then, the master unit side requests the respective input/output terminal devices BCU1 through BCUn to transmit the information CI to be used for judging controllability (information on the states of monitoring control objects such as the transformer tap state (position) and ON/OFF states of circuit breakers and disconnecting switches) (step A). Then, on the input/output terminal device BCU side, the respective input/output terminal devices BCU1 through BCUn receive the transmission request (of step A) (step B). Then, on the input/output terminal device BCU side, the respective input/output terminal devices BCU1 through BCUn transmit the information CI to be used for judging controllability (step C). Thereafter, the master unit side receives the information CI to be used for judging controllability from the respective input/output terminal devices BCU1 through BCUn (step D). Next, the master unit side judges controllability based on the received information CI, and when control is possible, it instructs the control object input/output terminal device BCU1 to execute control (step H). Then, the input/output terminal device BCU1 selected as a control object receives the control execution instruction (of step H) (step I), and executes control (step J).
The conventional method 1 and the conventional method 2 as aforementioned are not described in detail, however, for example, Japanese Published Unexamined Patent Application No. 11-134001 (Patent document 1) is available.
Patent document 1: Japanese Published Unexamined Patent Application No. H11-134001 (FIG. 1 and explanation thereof)
In the aforementioned conventional method 1 and conventional method 2, control is performed according to the aforementioned procedures, so that both of these require the time T1 from step A of control start to step J of control execution. The shorter the time from step A of control start to step J of control execution the better for more quick control. In the conventional method 1 and conventional method 2, the control object selection notification (step F) to notify of selection for control and the control execution instruction (step H) are both performed for only the selected input/output terminal device BCU1, so that in the input/output terminal devices BCU2 through BCUn that are not selected, multiple control may be performed even during control by the selected input/output terminal device BCU1, and therefore, it is preferable to prevent this multiple control.
The invention was developed in view of the conventional circumstances described above, and a first object thereof is to make the information necessary for judging whether control output is possible closer to the latest information than in the conventional method 1, or made the latest, and shorten the time from the control start to control execution.
Furthermore, the invention was developed in view of the conventional circumstances described above, and a second object thereof is to prevent multiple control of the input/output terminal devices that are not selected during control of the selected input/output terminal device.